Modern personal computers are, in many cases, more modular and can accommodate more add-on features than their predecessors. Detachable battery packs, mice, modems and keyboards, user-installable add-on cards, and processors and removable disk drives have all become common features of computer systems today.
With this modularity and the detachably connectable nature of many of these add-on devices, theft has become a problem. Because these detachably connectable devices are relatively easy to carry away and they are often designed to work with a variety of different computers, they are frequent targets for theft and misuse.
The field of laptop and notebook computers provides a good example of this problem. In the field of laptop and notebook computers, the demand for portability and functionality of components continues to play a powerful role. Consumers require small, lightweight components with functional capabilities rivaling those of traditional, stationary counterparts.
Especially important to portable computers are peripheral input/output devices such as modems, facsimile machines, local area networks (LANs), and memories. A modem, for example, allows a user to communicate with other computers over telephone lines. Such a modem may provide access to data at a base office from a portable computer without the need for storing that data in the portable computer.
A portable computer device, such as a modem, is often arranged on an internal board within the portable computer. Some portable computer configurations provide separate devices which may be carried by a user and attached to the portable computer when needed. Some peripheral devices, such as modems, have been designed to plug directly into sockets recessed within the body of the portable computer. Traditionally, a portable computer includes a separate socket and separate internal circuitry for each peripheral device. This requires extra space in the internal circuitry of the portable computer.
A modern portable computer, however, may have one or more sockets, each being able to accept a variety of peripheral devices. For example, a single socket on a portable computer may be able to interface with a modem, facsimile machine, LAN, and/or an external memory. Such a configuration obviously reduces the amount of space required within the computer.
In September of 1991, Personal Computer Memory Card International Association (PCMCIA), jointly with the Japan Electronics Industry Development Association (JEIDA), introduced an international standard, which defines the physical and electrical interface specifications for the interchangeability of memory and input/output cards. The assignee of the present invention, Intel Corporation, has additionally issued, on Dec. 20, 1991, a specification referred to as an Exchangeable Card Architecture (ExCA.TM.) specification. (ExCA is a trademark of Intel Corporation.) The ExCA specification describes interfaces which allow memory and input/output cards for portable personal computers of different manufacturers to be interchanged.
An integrated circuit card as referred to in this specification is an electronic device that is adapted for use with a personal computer and that generally is capable of performing one or more specific functions such as providing increased hard disk storage, providing local area network (LAN) communications or providing facsimile transmission and receipt capabilities. A card built to the PCMCIA standard is just one example of an integrated circuit card as described in the present invention. It will be apparent to one of ordinary skill in the art, however, that IC cards, modules and boxes that do not comply with the PCMCIA standard may also be used with the present invention.
An integrated circuit (IC) card designed and manufactured according to the PCMCIA specification, has a sixty-eight pin connector located at one end of the card for the sending and receiving of signals by the card. The IC card can be placed within a recessed socket within the computer, for example, to protect the card with the body of the computer surrounding the interface circuitry. Each IC card can be connected, used, and removed from a socket, interchangeably with other IC cards.
Along with the convenience and enhanced functionality of these IC cards lies a security problem. As discussed above, because of their small size, IC cards can be easily borrowed or stolen and the rising theft of IC cards has thus become a problem among users. Various approaches have arisen to combat this problem.
A first approach to the problem of theft of IC cards is to install a mechanical type of restraint. This approach is cumbersome to users in that it involves additional equipment where a goal of portable computing is to make computers and peripherals as small and lightweight as possible.
Another solution applies only to IC cards which provide external data storage, such as an IC card with a solid-state hard drive or an IC card with a rotating-disk hard drive installed thereon. According to this approach, data compression and/or data encryption onto the IC card hard drive is performed in such a way that data on the IC card's drive is useless to anyone without the same encryption or compression/decompression software. The thief is thus prevented from using the IC card only to the extent of reading pre-existing data on the disk. This second approach protects from unauthorized access to data on the IC card, but does not prevent unauthorized use of the IC card itself.
A third approach is similar to the second approach in that data is written on a hard drive using encryption techniques. Unlike the second approach, however, this third approach allows the IC card to encrypt data onto the system hard drive, which is built into the computer. Thus, the IC card acts as a security key. Without the particular IC card which directed the encryption, a user may not access the data on the system hard drive. Under this configuration, data placed on the system hard drive without the IC card encryption technique is unaffected, and only data encrypted by the IC card is protected. As with the second approach, this configuration does not prevent unauthorized use of the IC card itself, but only prevents unauthorized access to data encrypted by the IC card and stored on a system hard drive.
Similar issues exist with other detachably connectable computer devices.
Thus, a more convenient and comprehensive means for providing security for detachably connectable computer devices is needed.